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Topic: Body Bushing Installation (Read 110659 times)

I didn't see a how-to thread on this when I did a search in preparation to replace my body bushings, so I thought I would provide one that can hopefully be helpful to folks.

Credit where credit is due - I, like many others, got my instructions from a good thread here: http://www.nastyz28.com/forum/showthread.php?t=17406

After reading the great suspension thread in this section, I decided to go with the solid body bushings from Pro-touring F-Body. Thanks to 79T/AMan for a great product at what I felt was a very good price.

There are six body bushings between the subframe and other parts of our birds. On each side there is one at the very rear of the subframe between it and the body...

a second one just rear of the front fenderwell between the body and a bracket off of the subframe.

So that makes four. The final two are between the subframe and the radiator support at the front of the car on either side of the radiator. On the passenger side you can see the bushing and its bolt head between the radiator and the charcoal canister.

On the driver's side the bushing is under the battery tray, which you will have to remove to get to it.

There is a good pictorial location guide in the instructions Pro-touring F-Body and other vendors provide.

The first step is to soak the bushing bolts the best you can with PB Blaster or a similar product several times over a period of about two weeks if you have the patience. The bolts thread up into nuts that are "caged" or held in place by a metal cap over them. These cages have been known to break loose under heavy torquing. You don't want this to happen, since it is a PITA to get a grip on the nut in order to loosen the bolt if this happens. It is not a tragedy if the cage on the center bushing - just rear of the front fenderwell - breaks loose, as you can remove the inner fender and get access to it to re-secure the cage or hold the nut. However, there is no way to access the caged nut for the rearmost bushing bolts without cutting the floor inside the car to access the nut through the body shell.

Obviously, nobody wants to do that, so soak those bolts. Most have been in place for 30+ years exposed to the elements, and GM did us the favor of also using some loctite type stuff on them during assembly. You will see the blue on the bolts when you get them out. If you look at the link above you will see that some bolts corrode over time, thinning in the center to an hourglass shape, making them weaker. So all the more important to soak them good and be gentle when removing them. This is not meant to scare folks (as it did me for a long time). Just passing on the information I read to provide full information in one place.

Good advice I also read elsewhere is to go easy when you go to loosen the bolts. Impact wrench is not recommended. Use a 1/2" ratchet or a breaker bar and provide strong, even pressure. Don't jerk on it. Mine were pretty hard to break loose. It took some serious pulling on my breaker bar on several of them, but they did break loose without incident. My bolts actually looked pretty good. The old bushings did not.

Start by loosening up the back two bolts (not the ones near the radiator) on both sides. Don't back them all the way out, just give them a good few turns until you see the bushing loose enough to jiggle a bit.

Now do one side at a time. Start with the center bushing near the fenderwell. Remove the bolt completely (3/4" bolt head). The advice at the thread above says to then take the bushing and washer off the bolt and use it to put up through the alignment hole just next to the bushing bolt hole that more or less lines up with a hole in the body. This is to keep the subframe from shifting while you replace the bushings. I couldn't get the washer separated from the bolt or the bolt up through those holes, so I used a socket extension instead.

Leave the bushing in place for now and move on to remove the bolt from the rearmost bushing. The bolt is supposed to come out from the rubber bushing, but of course mine did not. It was stuck in the bushing. Problem is that the hole in the bottom of the subframe is not big enough to let the washer attached to the bolt come straight out. I had to fight with the bushing for a long time until I got one side of the washer below the bottom of the subframe and then was able to use a screwdriver to press the rubber bushing over and down to let the washer pass. On the other side the bolt came out the way it is supposed to.

So once you have those two bolts out on one side position a floor jack with a piece of 2x4 on top so that the block of wood contacts the body between the subframe and the bottom of the front fender. You will see where the firewall sheet metal overlaps with the body metal. That is where you want.

Now slowly jack up the body just enough to get enough separation between the body and the subframe to allow you to slide the top part of the old bushings out. They have little collars that you have to have enough height to get up out of the subframe.

Your old bushings will probably look like this, or worse

At least with the Pro-touring F-Body kit, you don't have to save any of the hardware. It comes with all new bolts, washers, everything.

Once you have the old bushings out put the new ones in following the directions with your kit. I went with the standard install that has the wide bushing part on top in between the body and subframe, with the collared and other pieces installed up from the bottom. The new bolt will thread up into the existing caged nut.

GM specs call for torquing the new bolts to 85 ft.lbs. The instructions with the Pro-Touring kit call for 95-100 ft.lbs.

Now repeat the process on the other side.

When you are done with the back four bushings it is time to move to the ones on the radiator support. In order to get clearance to remove these bushings you need to remove the two bolts on each side holding the radiator support to the subframe (3/4"). They are here:

This is a bit of a PITA because you have to get an open-end wrench down inside the subframe from the front to hold the head of each bolt while you remove the nuts (on the outside) with a socket. Getting the back bolts back in through the subframe when you are done is even more of a challenge (at least for me).

Then remove the bushing bolts from both sides at the locations pictured earlier. Use a 3/4" socket on the head on top and a 3/4" open end wrench to hold the nut on the bottom. You can reach to hold both at once. Here is what mine looked like

Once you have the bolt out with the top part of the bushing you will see the bottom part of the bushing with its metal collar sticking up through the radiator support like this (driver's side)

Put your jack with the block of wood under the radiator support just under where the bushing is and jack up gently to raise the radiator support up off the subframe enough to slide the bottom part of the bushing out. You may need to hammer down on the bushing metal collar to release it. I tried to jack up the radiator support from the center to do both sides at once, but that didn't work. You need to do one side at a time.

When you get both halves of the old bushing out it will look like this (passenger side)

While you still have the radiator support jacked up slide the bottom half of the new bushing between the rad support and the subframe and put the collared part down from the top along with the new bolt (head on top). Then you can let the jack down a bit at a time checking to make sure the parts of the new bushing seat together.

Then do the other side the same way. Torque the bolts to 55 ft.lbs. Now you are done, ALMOST. Don't forget to re-install the bolts holding the radiator support to the subframe. And then you are DONE.

Good write up and pics. I jsut added the same mounts to my 71 project when I refitted the new subframe. One thing I did was to coat all bolt threads with some anti-sieze compound. I figure I may want to undo them one day.

One quick word I can add, I have not verified if it helped yet as my subfram is in the process of being stripped of the suspension before I remove it for powdercoating, is how to access the cage nuts for the rear mounts.

If you look outboard of the frame hole for accessing the bolts, you will find oval shaped holes in the floorboard. If you reach inside, you can feel the cagenuts and the top of the bolt (it is tapered so you can feel the end of it). If you contort yourself a little (and have skinny fingers!) you can push in the straw from your can of PB Blaster and make contact with the bolt. This way when you spray it in, it will contact the bolt and the penetrant will migrate down the threads into the cage nut better.

I'm not sure about the thinner rubber bushing...the alloy ones I used are the same thickness at the firewall and rear mount.The bushing sits as you described....if you look in the first pic in this thread you can just see bushing hanging down from the top rubber mount.

I had a hard time telling whether there was a big difference at first. But once I got my much delayed front end alignment done - and found that all my shims had fallen out on the driver's side due to loose bolts - it really does feel much more solid. I was nervous about doing it, but was really easy.

Wish I would have had you here to do my fender vent stripe decals Tom. They look OK, but I got a little wrinkle in each side that left a bit of a mark when I got it smoothed.

I'm more likely than not going to replace my bushings as well and this read gave me a little bit of confidence to give it a shot.. Currently, the motor is out and i'm going to take the fenders, inner wheel wells as well as the nose off so I'm assuming this will make it much easier?? Also, going to replace the radiator core support so this would need to be done anyway...

The replacements that come in some kits are not like the originals with the pointed end, they are just high tensile regular bolts with large washers. I'd take your old bolts to a fastener store and just replace them with grade 8 bolts.

Excellent write-up but I wanted to add some points since I just did this on my '73 Trans Am. First, for the early cars the solid bushings probably won't fit without some filing to enlargen the hole. The instructions that come with the kit even say that the bushings may not fit on 70-73 Firebirds and Camaros without some modifications to make the hole larger. At least one person with a '74 TA also reported they had to modify the hole to make it larger. I am only talking about the hole in the core support, not the hole in the frame. Second, for the early cars the core support sits underneath the sub-frame and the bolts install from the bottom up versus top down as show in the example in this post. The assembly manual for the '73 shows the right orientation for the bolts and core support.

I'm replacing the factory rubber bushings on my 80 TA. They sure appear to be the factory ones given their deterioration. When I got to the radiator support bushings, I removed the bolt and there the body bushings on the top side of the radiator support is about 1" thick but I don't see any bushing between the frame and the bottom of the radiator support. There should be bushing material sandwiched in that location, correct?

Logged

1980 Pontiac Trans Am, 455 Oldsmobile1970 Blazer with a 400 sbc and 4" lift Roadworthy!1969 K20 with a 454, a bit of lift and 35's

I assume the 80 is same as my 78, so yes - there should be a rubber bushing around a metal collar that sticks up through the hole in the radiator support. The radiator support doesn't just sit flush on the subframe. Are you saying that is the case with yours?

Yes, I can't see any bushing material between the radiator support and the subframe on either the drivers or passenger side. I read in a post on another site that deleting the bushing in this location gives the most "wedge" possible. Given that the bushings appear to be original I'm a little surprised to learn that maybe the ones in this location were removed, but that is sure what it is sounding like. The bolts were both tight so it isn't like the bushings completely deteriorated as that would have left the bolts lose.

Assuming these were actually removed, I've got to decide whether to put the new ones in where they should be. My TA has a swapped in 455 Olds and I do note poor hood to shaker clearance so I guess that could help with that issue.

Logged

1980 Pontiac Trans Am, 455 Oldsmobile1970 Blazer with a 400 sbc and 4" lift Roadworthy!1969 K20 with a 454, a bit of lift and 35's

Got a couple pics this morning and noticed that the bushings at the radiator support are actually in very good shape which leads to me believe a prior owner did put in new bushings in this location and went without the piece that goes between the frame and the radiator support. The driver side had a lock washer while the passenger side doesn't which also leads me to believe these have been changed.

So now I need to decide whether I go with the tall bushing between the frame and the radiator support which is how I've got the rear subframe bushings or go with the smaller piece here for a slight wedge. I'm inclined to go with the smaller piece to have a slight wedge as a compromise between how it is now with no bushing in that location as opposed to putting in the taller bushing. Again, gaining a little clearance for the shaker will be beneficial.

Logged

1980 Pontiac Trans Am, 455 Oldsmobile1970 Blazer with a 400 sbc and 4" lift Roadworthy!1969 K20 with a 454, a bit of lift and 35's

My 76' is getting the solid mounts and a set of sub-frame connecting rails installed next week. Has anyone done this combo, and if so did you bolt or weld your connectors on? -- Also, I'm curious as to what the tilt (or rake) accomplishes with the radiator mounts.

I went to put my solid body mounts in today and one side went pretty good.The passenger side didn't go so well.The back body bolt loosen just fine, so i went to loosen the front one by the fender well and it just spins and won't come out.So the nut must have broke loose and just spins.I can et my hand in there and feel the bolt spin.What is my next step to getting the bolt out??It's a 79 TA.Thanks Matt

Thats not a bad one like the floor mounted nut.....I've heard guys get a friend to jam a big screwdriver in next to the nut to hold it.....or you may be able to knock the cage down over the nut to hold it.....or worst case, get a MIG in there and try and tack the nut.

Finally put in my pro touring f-body bushing kit the other day. It was a little putsy since it was the first time I'd ever done it but everything went very smoothly! All of the bolts came right out with the exception being the rear most bushing under the drivers floor. The washer had "become one" with the bolt. I just cut the bushing out and all was well! Soaking those bolts with a good penetrant like PB blaster from the top down (when possible) is really the key!

Started doing mine and all were pretty tight but I did get 5 out ok. The last one (rear passenger side) broke off in the middle of the bolt so now I have a little bit of it sticking out but need to remove it without breaking the cage nut loose too. Any thoughts on best way to get this out?

PTFB bushings are made of 6061 T-6 aluminium with steel inserts. I bought mine from Summit, they are Energy Suspension peices. Worked perfect (after I had to repair the rusted out mounting holes in the frame)

I've used the PST polygraphite ones...they worked fine. Full kit came with all the hardware. used them on my 77 T/A.This time, for my 71 project, I bought PTFB alloy ones, they fitted easily and are step locked in design so the upper/lower bushes are locked together.

On both the PST and PTFB sets, you may have to file out the rad support mounting hole a little for the bushes to fit through...apparently, it depends on the year model. I had to file out my 71's rad support holes a little.

Here is a suggestion for athe stripped cage nut.I was watching one of those shows on spike yesterday, trucks or muscle car one of those, And the cut out sround the hole where it is and welded a nut to a washer and then welded the waher to the frame and grinded it smooth.

I just installed the solid bushings from PTFB, and they worked fantastic. It completely tightened up the whole front end of my car. I was immediately satisfied. I haven't even driven it yet, but can tell that it will be noticeably tighter.

1. I like to give a generous thanks to pozarcar for the excellent write up with pictures. I could not have done this without it.2. This project takes quite a bit of time. Fortunately, it can be divided into 4 parts; the back left and right two bolts and then the front left and right. It took me 4 days, but others who are more experienced can probably do it faster. I also rust treat and paint as I go so that slows me down a little.3. The heads on my bolts were 15/16”; this probably differs with the year of the car.4. I used a ½” bolt with a nut in the center mount alignment holes, although it never seemed to be needed.5. The center two bolts were really torqued in. I needed a foot long pipe on the ½” breaker bar with my feet against the car to break them loose.6. The rear bushings have alignment collars that are about 1” long. This means the body must be separated from the sub-frame by at least that much. I used the floor jack and a 2x4 and jacked as much as I could and only got ½” separation. I then used a bottle jack in another area and got a ¼” more, but still not enough. The sub-frame connectors were holding the body to the frame at the front leaf spring eye. I finally had to use a wedge (as for wood splitting) and drove it in between the connector and one of the floor pan braces to get enough clearance.7. Not thinking, I removed the wedge and went to the middle mount. It was the same story; I could not jack it up enough to remove the old mount. I had to pound the wedge back in to get it out.8. I used the thick washers between the body and the frame for the rear two bushings. The sub-frame connectors already hit the floor pan so this was my only choice.9. In the front, unthread the ¾” bumper support bolts in the front to the end of the bolt and then hit them with a hammer to drive them out. You can reach in through the front into the sub-frame to reinstall them.10. At first I didn’t understand what the radiator support was. It is the U-shaped channel that runs under the radiator side to side (my bad). Using a 2x4, I jacked this up until I lifted the front end off the jack stand and it still was not enough clearance to get the old bushing out. I then had to get a pry bar to get the old bushing out.11. I put the thick bushing in on the front right side. Upon finishing, I immediately noticed the wheel well clearance was larger (my wife wishes I was this sensitive). I did not want more of a wheel well open or a sunken hood scoop, so I redid the front right with the thin washer. When I was done with both fronts, I read the directions provided with the mounts, and found out what I had done was the recommended configuration (thin-thick-thick).

Thank you all so much for this thread and all the follow up posts. I have 2 nearly identical 1973 Trans Ams. Both have Hotchkis TVS kits, KYB shocks, and moog front end rebuild kits. One car had brand new poly body mounts, the other had the stock, 39 year old, crumbling rubber body mounts. The one with the poly mounts handles like a new car - amazing for 39 year old technology. The one with the stock desintigrated mounts handled like a tug boat - pitching and rolling and rattling and creaking - even with all of the Hotchkis components. I swapped my body mounts for poly myself with the help of this thread and the difference was literally night and day. All the suspension upgrades in the world will only exaggerate insufficient body to frame contact. It took all day, and for a while there, I was convinced I was doing something wrong. The body just wouldn't lift off of the frame. I finally got brave with the jack and the body finally separated. I used the black poly mounts with LIBERAL doses of silicone grease. I did end up re-using the bolts at the radiator support in order to re-use the flat threaded caps in the frame. Of course, installation was much easier and alot quicker than removal! I was thrilled to have swapped them myself and made such a HUGE difference in this car's ride.